The present invention relates to an apparatus and a method for controlling a volume in digital telephones such as second generation mobile telephone terminals, third generation IMT 2000 image mobile telephone terminals, and ISDN (integrated service digital network) terminals. In particular, an apparatus and a method in accordance with an embodiment of the present invention measure background noise and adjust volume of received sound and/or ring signal accordingly.
As telephones are popularized, they are used in various environments. Especially, as mobile telecommunication technology progresses, more and more people use mobile phones and telephone calls are made at any place at any time. However, large ring signal and loud voice for telephone sometimes bother people around the telephone user.
In such cases, usually telephone users increases voice tone or pitch because of small received sound, and the users forgets volume control of the ring signal because it is hard to adjust telephone ring signal rather than because they are rude. Therefore, if there are devices that are able to adjust telephone ring signal and volume of received sound automatically in response to various environments, the cases of inconvenience stated above will be definitely decreased.
Regarding this matter, Korea Patent Application No. 1991-025518 disclosed a technology adjusting volume of received sound automatically. The invention relates to an automatic level adjustment apparatus, which adjusts volume of received sound automatically in response to volume of transmitted sound. In this invention, since background noise doesn""t perform any important role to adjust volume of received sound, volume of received sound may be varied on the basis of habit of telephone users.
Korea Patent Application No. 1995-035336 disclosed a telephone that adjusts volume of received sound automatically in response to background noise. The telephone is equipped with a microphone for collecting background noise and the collected background noise is utilized for adjusting volume of received sound automatically. Since the telephone measures background noise without discriminating between voice and non-voice, sometimes voice of telephone users are treated as noise, which may cause serious problem.
In addition, since additional circuitry is necessary to add such features to conventional digital telephones, the previous technologies causes cost increase and large sized telephones. Consequently, the previous technologies are not appropriate for state of the art digital telephones that pursue low cost, low power consumption, and low weight.
An apparatus and a method for volume control in digital telephone are provided. The digital telephone includes ring signal source, ring signal speaker, DSP (digital signal processor), and ADC (analog-digital converter). The ring signal source stores various sounds at transceiver and terminal. The ring signal speaker transmits ring signal provided by the ring signal source at in detecting ring signal. The DSP (digital signal processor) encodes and decodes input signal with voice codec. The ADC (analog-digital converter) converts analog signal into digital signal. The analog signal is provided from microphone of transceiver.
An apparatus and a method for volume control in digital telephone in accordance with an embodiment of the present invention includes background noise input part, input signal amplitude measurement part, and volume adjustment part. The background noise input part collects background noise and converts the noise into digital signals. The input signal amplitude measurement part measures amplitude of the background noise. The volume adjustment part adjusts ring signal amplitude provided from ring signal source in accordance with the amplitude of the background noise and generates the adjusted ring signal to ring signal speaker.
Preferably, the background noise input part includes a microphone of conventional transceiver and an ADC.
Preferably, the volume adjustment part compares sound pressure level of the measured background noise with unique minimum/maximum sound pressure of a digital telephone, adjusts ring signal volume on the basis of the minimum sound pressure if sound pressure level of the measured background noise is lower than unique minimum sound pressure of a digital telephone, adjusts ring signal volume on the basis of the maximum sound pressure if sound pressure level of the measured background noise is bigger than unique maximum sound pressure of a digital telephone, adjusts ring signal volume in proportion to the measured sound pressure level of the measured background noise if sound pressure level of the measured background noise is between the unique minimum sound pressure and the unique maximum sound pressure of a digital telephone.
An apparatus for volume control in digital telephone is provided. The digital telephone includes ring signal source, ring signal speaker, DSP (digital signal processor), ADC (analog-digital converter), and DAC (digital-analog converter). The ring signal source stores various sounds at transceiver and terminal. The ring signal speaker transmits ring signal provided by the ring signal source at in detecting ring signal. The DSP (digital signal processor) encodes and decodes input signal with voice codec. The ADC (analog-digital converter) converts analog signal into digital signal. The DAC (digital-analog converter) converts digital signal into analog signal. The analog signal is provided from microphone of transceiver and the digital signal is provided from voice codec.
An apparatus for volume control in digital telephone in accordance with an embodiment of the present invention includes background noise input part, voice/non-voice discrimination part, input signal amplitude measurement part, and volume control part. The background noise input part collects background noise and converts the noise into digital signals. The voice/non-voice discrimination part receives the collected background noise, discriminates between voice and non-voice, and isolates pure noise. The input signal amplitude measurement part measures amplitude of the isolated pure noise. The volume control part adjusts volume of received sound in accordance with the measured amplitude of the isolated pure noise and provides to speaker at receiver. The received sound is provided from the speech codec.
Preferably, the background noise input part includes a microphone of conventional transceiver and an ADC.
Preferably, the volume control part is equipped with ring signal adjustment capability. The ring signal adjustment capability adjusts ring signal in accordance with the measured amplitude of the isolated pure noise and provides to ring signal speaker.
A method for volume control in digital telephone with DSP (digital signal processor) is provided. A method for volume control in digital telephone with DSP (digital signal processor) in accordance with an embodiment of the present invention includes ring signal adjustment step and received sound adjustment step. The ring signal adjustment step is for setting up a call, measuring background noise, and adjusting amplitude of ring signal in accordance with the measured background noise when a phone call is received at standby state. The received sound adjustment step is for collecting background noise from call-start to call-end, measuring amplitude of the background noise, determining level of received sound on the basis of the measured amplitude of the background noise, and adjusting amplitude of received sound.
Preferably, the amplitude of ring signal is determined by following steps. A step is for collecting background noise using microphone at a transceiver. A step is for converting the collected noise into digital signal. A step is for measuring sound pressure level of the digital signal. A step is for comparing sound pressure level of the measured background noise with unique minimum/maximum sound pressure of a digital telephone. A step is for adjusting ring signal volume on the basis of the minimum sound pressure if sound pressure level of the measured background noise is lower than unique minimum sound pressure of a digital telephone. A step is for adjusting ring signal volume on the basis of the maximum sound pressure if sound pressure level of the measured background noise is bigger than unique maximum sound pressure of a digital telephone. A step is for adjusting ring signal volume in proportion to the measured sound pressure level of the measured background noise if sound pressure level of the measured background noise is between the unique minimum sound pressure and the unique maximum sound pressure of a digital telephone.
Preferably, the received sound adjustment step includes following steps. A step is for converting the collected noise into digital signal. A step is for isolating pure noise from transmitting signal by discriminating between voice and non-voice from in the digital signal.
Preferably, the step for determining level of received sound and adjusting amplitude of received sound in the received sound adjustment step employ 10xcx9c30 ms unit as a basic data processing unit.
Preferably, the level of received sound in the received sound adjustment step comprises several stages and is determined by comparing sound pressure of the measured background noise with reference sound pressures of the stages.
Preferably, the step for determining the level of received sound sets the determined level as level for current frame for preventing errors in discriminating between voice and non-voice and frequent change of levels in response to accidental noise if same levels are continued for certain number of frames and level of current frame is changed into different level.
Preferably, the step for determining the level of received sound maintains the level of received sound with input level if the determined level of received sound is higher and lower than the level of previous frame and thereby overflow or underflow is caused in increasing or decreasing volume of received sound.
A method implemented in a computer system for volume control in digital telephone with DSP (digital signal processor) is provided. A method implemented in a computer system for volume control in digital telephone with DSP (digital signal processor) in accordance with an embodiment of the present invention includes ring signal adjustment step and received sound adjustment step.
The ring signal adjustment step includes following steps. A step is for setting up a call. A step is for collecting background noise using microphone at a microphone of a transceiver. A step is for converting the collected noise into digital signal. A step is for measuring sound pressure level of the digital signal. A step is for comparing sound pressure level of the measured background noise with unique minimum/maximum sound pressure of a digital telephone. A step is for adjusting ring signal volume on the basis of the minimum sound pressure if sound pressure level of the measured background noise is lower than unique minimum sound pressure of a digital telephone. A step is for adjusting ring signal volume on the basis of the maximum sound pressure if sound pressure level of the measured background noise is bigger than unique maximum sound pressure of a digital telephone. A step is for adjusting ring signal volume in proportion to the measured sound pressure level of the measured background noise if sound pressure level of the measured background noise is between the unique minimum sound pressure and the unique maximum sound pressure of a digital telephone
The received sound adjustment step includes following steps. A step is for collecting background noise from call-start to call-end. A step is for converting the collected noise into digital signal. A step is for isolating pure noise from transmitting signal by discriminating between voice and non-voice from in the digital signal. A step is for measuring sound pressure level of the pure noise. A step is for determining level of received sound on the basis of the measured sound pressure of the background noise. A step is for adjusting amplitude of the received sound.